1. Field
The inventive concept relates to semiconductor memory devices and methods of manufacturing semiconductor memory devices. More particularly, the inventive concept relates to semiconductor memory devices including vertical pillar type of transistors and methods of manufacturing semiconductor memory devices having vertical pillar type of transistors.
2. Description of the Related Art
Recently, the degree of integration of semiconductor memory devices has been improved through the use of vertical pillar type of transistors in the cell regions of the devices. In this respect, a vertical pillar type of transistor includes a semiconductor pillar extending perpendicular to the substrate. As the degree of integration of semiconductor memory devices has been further increased, the widths of the semiconductor pillars, as well as the distance between adjacent semiconductor pillars have become smaller. Accordingly, the wirings in the semiconductor memory device are becoming narrower and are being spaced closer together. Therefore, the resistance of the wiring is becoming greater, and electrical shorts between adjacent wirings are occurring more frequently. As a result, highly integrated semiconductor memory devices that include vertical pillar type of transistors may exhibit poor response speed and in general, may possess poor electrical characteristics.